nixos-config/components/virtualisation/virtualbox.nix

{
  config,
  lib,
  pkgs,
  ...
}:
with lib;
{

  options.components.virtualisation.virtualbox.enable = lib.mkOption {
    type = lib.types.bool;
    default = config.components.virtualisation.enable;
  };

  config = mkIf config.components.virtualisation.virtualbox.enable {

    virtualisation.virtualbox = {
      host.enable = true;
      guest.enable = true;
    };

    users.extraGroups.vboxusers.members = [ config.users.users.mainUser.name ];

  };

}